Rapid infusion system

ABSTRACT

A rapid infusion system for the intravenous delivery of fluids at standard and rapid flow rates. The system includes a pump assembly, a drive assembly to power the pump, and a fluid containment system that keeps the infused fluid out of direct contact with the pump assembly and that is preferably disposable and removable. In one embodiment the drive assembly includes a differential drive that interacts with more than one motor. In one embodiment, the pump assembly includes a roller pump and the pump chamber is a collapsible, preformed tube that is preferably attached to a pump cartridge frame. Optionally, the system includes a self-leveling drip chamber and the fluid containment system is disposable and includes a pump cartridge containing the drip chamber and the pump chamber, I.V. tubing, outlet infusion tubing, and a heater cartridge.

RELATED APPLICATION

This application is a continuation of U.S. Ser. No. 09/510,139 filedFeb. 22, 2000 now U.S. Pat. No. 6,554,791, which claims priority to U.S.Provisional Application No. 60/156,674 filed Sep. 29, 1999.

FIELD OF THE INVENTION

The invention relates to medical devices and methods for the infusion offluids such as blood, blood products, and medications into a patientrequiring circulatory volume replacement, with a capability for infusionover a range from slow to extremely rapid flow rates.

BACKGROUND OF THE INVENTION

A variety of clinical circumstances, including massive trauma, majorsurgical procedures, massive burns, and certain disease states such aspancreatitis and diabetic ketoacidosis can produce profound circulatoryvolume depletion, either from actual blood loss or from internal fluidimbalance. In these clinical settings, it is frequently necessary toinfuse blood or other fluids rapidly into a patient to avert seriousconsequences.

In the past, the replacement of large amounts of fluids has been a majorproblem to the medical or surgical teams attending a patient with theseacute needs. A common method of rapid infusion involves the simultaneoususe of a plurality of infusion sites. Frequently, a plurality of medicalpersonnel are required to establish and oversee the various infusionsites and to personally ensure the flow of fluids from their respectivecontainer bags. This method may be limited by the number of peripheralor central sites that can be physically accessed in a given patient, thenumber of people attending the fluids being infused, as well as theefficiency of infusing the fluids during a dire, hypovolemic event. Itis not uncommon for four to five anesthesiologists or technicians tostand in attendance during transplant operations lasting more thantwenty-four hours attempting to infuse massive quantities of bloodthrough five or six venous catheters.

Patients who have undergone massive trauma or surgery such as livertransplantations or other elective procedures may require voluminousquantities of fluids to maintain a viable circulatory state. Although itis not uncommon for an anesthesiologist or surgeon in a major trauma andtransplantation center to encounter massive exsanguination of ten litersor more, it is unusual to successfully resuscitate a patient with suchmassive blood volume loss using traditional methods.

While the potential need for rapid infusion is present in a number ofcommon clinical situations, the actual need is unpredictable and mayarise suddenly during the course of treatment or surgery. Therefore, itwould be advantageous to have a system that could rapidly transitionfrom normal infusion to rapid infusion with minimal operationalintervention.

In patients suffering blood loss, measuring the pressure in the largecentral veins (central venous pressure or C.V.P.), is a good objectivemethod for assessing the efficacy of volume replacement. A low C.V.P.indicates that the patient does not have adequate intravascular volumeand thus further fluid resuscitation is necessary. A high C.V.P. is anindication of volume overload and can result in heart failure andpulmonary edema (or fluid) in the lungs. Presently, C.V.P. is mostcommonly measured by placement of a large catheter in the patients neckthat is connected to a pressure transducer. This transducer convertspressure changes into an electrical signal that is displayed on anoscilloscope-type monitor.

Intensive care units and operating rooms are usually the only hospitalareas capable of measuring C.V.P. In an emergency department setting,fluid administration is gauged empirically using mainly the patient'sblood pressure and pulse to assess the adequacy of volume replacement.

Rapid infusion devices are best used while monitoring C.V.P. The volumeand rate of flow into the patient can then be quickly and accuratelyadjusted to sustain an adequate C.V.P., lessening the chances ofcomplications of heart failure and pulmonary edema from fluid overload.

The prior art contains a number of devices and methods that haveattempted to address the clinical need for rapid intravenous fluidinfusion.

U.S. Pat. No. 5,840,068 to Cartledge discloses a device and method forthe rapid delivery of an infusion of blood and/or volume expanding fluidto a patient. The device includes a pump system that interfaces with afluid housing system.

U.S. Pat. No. 5,061,241 to Stephens, et al. discloses a rapid infusiondevice capable of high volume pumping. The device includes a permanentunit that includes a base portion that houses an AC/DC motor, a rollerpump, and other associated gauges and switches. A disposable unitincludes a fluid housing, heat exchange component, and associated tubingleading to the roller pump. The roller pump increases the volume offluid being pumped by increasing the r.p.m. of the pumping unit andincludes a pressure control valve.

U.S. Pat. No. 4,747,826 to Sassano discloses a portable infusion systemconsisting of supply sources, fluid housings, and associated tubes andvalves leading to an infusion pump which can be a centrifugal or aroller head occlusive pump.

U.S. Pat. Nos. 4,187,057 and 4,537,561 to Xanthopoulos discloseperistaltic infusion pumps employing disposable cassettes to house theinfused fluid. In the '057 patent, the fluid conduit is held in thecassette in an arcuate configuration for its active interface with apump rotor assembly. In the '561 patent, the fluid conduit is held inthe cassette in a linear configuration for its active interface with apump rotor assembly. It appears that the pumps can provide only routineinfusion rates.

U.S. Pat. No. 4,410,322, to Archibald discloses an intravenous infusionpump that employs a piston-cylinder pump and a disposable pump chamber.The pump chamber contains a linear series of diaphragm enclosures thatpropel the infused fluid from the action of the pump cycles.Dielectrical sensors are employed to detect the presence of air bubblesin the disposable pump chamber. When air is detected by the system, analarm is sounded for operator intervention.

Intravenous infusion rates may be defined as either routine, generallyup to 999 cubic centimeters per hour (cc/hr), or rapid, generallybetween about 999 cc/hr and 90,000 cc/hr (1.5 liters per minute) orhigher. Most prior art infusion pumps are designed for medicationdelivery and are limited in their performance to the routine range ofinfusion rates. Such pumps are not capable of rapid intravenousinfusion. Although some prior art infusion systems can deliver rapidinfusion, those prior art rapid infusion devices are physically large,complex systems that require dedicated operation by skilled technicians.

Accordingly, what is needed is a device for rapid infusion that iscompact and easily operated by conventional medical personnel in thecourse of their other duties. What is also needed is a low to high speedinfusion device that utilizes a sterile, disposable fluid containmentsystem that can be readily attached and removed from a separate pumpsystem.

SUMMARY OF THE INVENTION

The rapid infusion system described herein is an adjustable mechanicalpumping system for the intravenous delivery of fluids such as, but notlimited to, blood, blood products, physiologic fluids, and medications.The present invention has several novel features that distinguish therapid infusion system from the prior art. The present invention is muchsafer than prior art devices in that the present invention includes aself-leveling drip chamber that decreases the possibility of airentering the system thereby protecting the patient from air embolism. Inaddition, the self-leveling drip chamber adds to the efficiency and easeof use because the operator will not have to shut the system down topurge air from the lines.

Another advantage of the present invention is an integrated motor drivethat allows the device to deliver a wide range of flow rates of fluidsfrom a unit that is small and compact. In addition, the presentinvention provides a wide variety of flow rates with no change in theconfiguration of the drive system.

Another advantage of the present invention is the pump chamber and dripchamber are in one disposable unit that is easily installed by theoperator of the device. All of these unique features provide a rapidinfusion system that is (1) small, light-weight and relativelyinexpensive because of the simple design of the device; (2) flexiblebecause the device can deliver wide ranges of flow rates of fluidswithout the need to change the configuration of the drive system; (3)safe because the possibility of air entering the delivery tubing isvirtually eliminated; and (4) easy to use because the pump chamber andthe drip chamber are in one, easily installed unit. The presentinvention is capable of rapidly delivering fluids with greatly reducedoperational demands to a patient suffering from acute hypovoleria. Therapid infusion system offers improved mechanical functions and desirableoperational improvements over previously known systems and practices inthe management of critical, life- threatening situations.

In one preferred embodiment, the rapid infusion system includes a pumpassembly, a drive assembly to power the pump, and a fluid containmentsystem that keeps the infused fluid out of direct contact with the pumpassembly and that is preferably disposable and removable. The systemoptionally includes components such as a pressure sensor and controller,a temperature sensor and controller, a filter to remove any occlusivematerial from the fluid, an automatic self-leveling system to keep thefluid in the drip chamber at an appropriate level for maximal deliveryefficiency, and a sensor system to detect the presence of air bubbles inthe fluid in conjunction with a switch that can stop the flow in theconduit in response to a detected air bubble of a dangerous size.

The flow rate of the pump advantageously is continuously adjustable and,preferably, can provide fluid flow rates from less than 20 cc/hour tomore than 1,500 cc/minute. In a preferred embodiment, the pump is aroller pump and is connected with a drive assembly using a differentialassembly to provide seamless transition from standard flow rates to highflow rates.

The present system provides a cost effective, yet safe method ofhandling sterile infusions, as all components of the system thatphysically contact the infused fluid are contained within or attached toa sterile, disposable cartridge designed for single use. In oneembodiment, the single use pump cartridge includes a section ofpre-formed tubing serving as the pump chamber. The cartridge includes adrip chamber that is self-leveling. Optionally, the system may include atemperature sensor at the output of the temperature controller formeasuring and adjusting the fluid temperature to maintain thetemperature within acceptable limits. Other embodiments of the systemmay also incorporate other monitoring sensors and feedback devices toallow adjustments to be made by the infusion system in response tophysiologic measurements, such as central venous pressure, pulmonaryarterial wedge pressure, urine output, pulse, mean arterial bloodpressure, and similar parameters. Still other embodiments of the systemmay incorporate other monitoring sensors and feedback devices to alloweither quantitative or qualitative adjustments in the infusium inresponse to in vivo sensors measuring parameters such as arterial pH,serum potassium, serum glucose, and other physiologic or chemicalfactors. The system also preferably includes a user display, whichdisplays parameters including fluid temperature, line pressure, fluidflow rate, and total volume of fluid infused.

A further advantage of this system is that it does not require dedicatedtechnical personnel for its operation, and it can readily be programmedand operated by nursing or emergency personnel in the course of theirother patient care duties. Yet another advantage of this system is anelectronic control system that allows precise, in vivo monitoring ofblood pressure and/or chemistries, and the system may be programmed tomake precise and automatic adjustments of the infusion rate to thepatient based upon the monitored parameters.

An object of the present invention is to provide an adjustable systemthat is capable of standard to high volume infusion of fluids into apatient requiring such treatment.

A further object of the present invention is to provide a single-use,disposable fluid containment system for an infusion system thatinterfaces with permanent pump and control systems to provide safe,sterile, and contamination-free delivery of fluids to a patient.

Another object of the invention is to provide a pump cartridge for aninfusion system that is fluid self-leveling.

Still another object of the invention is to provide a rapid infusionsystem that can deliver fluid at normal and rapid rates, and that cansmoothly transition between normal and rapid infusion rates. In oneembodiment, this smooth transition is achieved using a differentialdriver assembly that interacts with more than one motor and drives thepump.

BRIEF DESCRIPTION OF THE DRAWINGS

Referring to the drawings:

FIG. 1 is a front elevational view of one embodiment of the rapidinfusion system showing the housing, the control panel, a heatercartridge, and the disposable infusion pump cartridge in theirrespective operational positions within the rapid infusion system.

FIG. 2 is a partially assembled view showing the interaction between thedrive assembly and the pump roller head assembly in one embodiment ofthe rapid infusion system.

FIG. 3 is an exploded view of the drive assembly used in one embodimentof the rapid infusion system.

FIG. 4 is an exploded view of a differential box assembly used in oneembodiment of the rapid infusion system.

FIG. 5 is a cross-sectional view of a differential box assembly used inone embodiment of the rapid infusion system.

FIG. 6 is an exploded view of a yoke assembly used in one embodiment ofthe rapid infusion system.

FIG. 7 is an exploded view of a gear shaft assembly used in oneembodiment of the rapid infusion system.

FIG. 8 is an exploded view of a bearing plate assembly used in oneembodiment of the rapid infusion system.

FIG. 9 is an exploded view of a worm bevel gear assembly used in oneembodiment of the rapid infusion system.

FIG. 10 is an exploded view of a stepper gear assembly used in oneembodiment of the rapid infusion system.

FIG. 11 is an exploded view of a stepper motor assembly used in oneembodiment of the rapid infusion system.

FIG. 12 is an exploded view of a gear box assembly used in oneembodiment of the rapid infusion system.

FIG. 13 is an exploded view of a high speed motor assembly used in oneembodiment of the rapid infusion system.

FIG. 14 is an exploded view of a mount plate assembly used in oneembodiment of the rapid infusion system.

FIG. 15 is an exploded view of a pump roller head assembly used in oneembodiment of the rapid infusion system.

FIG. 16 is an exploded view of a pivot arm assembly used in oneembodiment of the rapid infusion system.

FIG. 17 is a view of a partially assembled pump roller head assemblyused in one embodiment of the rapid infusion system.

FIG. 18A is an exploded view of the IV infusion tubing system used inone embodiment of the rapid infusion system.

FIG. 18B is a perspective view showing the interaction between the pumphead and the disposable infusion pump cartridge in one embodiment of therapid infusion system

FIG. 19 is an exploded view of one embodiment of the disposable infusionpump cartridge assembly.

FIG. 20 is another exploded view of one embodiment of the disposableinfusion pump cartridge assembly, showing details from below thecartridge unit.

FIG. 21 illustrates the components of the automatic fluid self-levelingsystem in the exemplary system.

FIG. 22 details the interface between the drip chamber of the infusionpump cartridge and the diaphragm pump in the fluid self-leveling systemin the exemplary embodiment of the system.

FIG. 23 details the heater module components and their relationships inthe exemplary embodiment of the system.

FIG. 24A is an exploded view of the components of the pole clampassembly used in the exemplary embodiment of the rapid infusion system.

FIG. 24B is an assembled view of the pole clamp assembly used in oneembodiment of the rapid infusion system.

FIG. 25 is a block diagram illustrating the electronic control system ofan exemplary embodiment of the rapid infusion system.

FIG. 26 details the electronic control/display user interface for anexemplary embodiment of the rapid infusion system.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A system for rapid, intravenous infusion of a fluid is disclosed. Theterm “fluid” as used herein refers to blood, plasma, platelets,cryoprecipitates, blood products, physiologic fluids, medications, andother blood products and blood components. The system includes a dripchamber having an intake port for receiving the fluid and an outlet portfor dispensing the fluid. The drip chamber is preferably included in apump cartridge that may also include the pump chamber. A pump assemblypropels the fluid through the system, and can include a gear pump, aturbine pump, a roller head occlusive pump, a nonocclusive centrifugalpump, or the like. The pump advantageously is adjustable and can providefluid flow rates from less than 20 cc/hour to more than 1500 cc/minute.

The system further includes a drive assembly for driving the pump andone or more motors for powering the drive. Optionally, the system caninclude a fluid temperature controller, one or more optional filters toremove occlusive materials from the fluid, optional fluid pressuresensors, temperature and bubble sensors, tubing, catheters, and otherconduits for infusing the fluid into the venous system, and conduits forconveying the fluid to and from each of the components of the system.Additionally, the system can include an automatic self-leveling systemto keep the fluid in the drip chamber at an appropriate level formaximal delivery efficiency. Another optional component is a sensorsystem to detect the presence of air in the fluid in conjunction with aswitch that can stop the flow and optionally sound an alarm in theconduit in response to a detected air bubble of a dangerous size.

In a preferred embodiment, the rapid infusion system described herein iscomposed of two major portions. One such portion includes permanentequipment, i.e. equipment that does not physically contact the infusedblood or fluid and thus need not be sterilized. In one embodiment, thepermanent components include the pump gears or rollers, the driveassembly, one or more pump motors and related controls, optionalmonitoring equipment such as a C.V.P. monitor and related controls, anoptional heating element and related controls, and an attachmentadapter. The other portion includes optionally removable, disposablecomponents such as the fluid containment system including a dripchamber, pump chamber, tubing, optionally a fluid heater cartridge andmultiple conduits to access one or more IV bags or reservoirs.

As used herein, the term “pump chamber” refers to the region in thefluid flow path where motion is imparted to the fluid. In some cases,motion is imparted to the fluid by the action of a pumping mechanismlocated outside the pump chamber. Accordingly, when the pump is a rollerhead occlusive pump, a peristaltic pump, or a diaphragm pump, forexample, the pump chamber can be separated from the pumping mechanismand the pumping mechanism does not contact the fluid. Since the pumpingmechanism does not contact the fluid, it can be a permanent orsemi-permanent piece of the infusion system. Alternatively, it can beincluded in the disposable fluid containment system.

In other cases, when the pump is a gear pump, a turbine pump, or anonocclusive centrifugal pump, the pumping mechanism is contained withinthe pump chamber and fluid does contact the pumping mechanism. In thiscase the pumping mechanism, at least those portions that contact thefluid, is generally included as part of the disposable fluid containmentsystem.

In one embodiment, the pump chamber forms a portion of a disposable pumpcartridge. The pumping mechanism may also be included in this disposablecartridge.

Optionally, the system may further include temperature sensors at theinput and output of the temperature controller for measuring andadjusting the fluid temperature to maintain the temperature withinacceptable limits. The system may also incorporate monitoring sensors ordevices to allow measurements and possibly adjustments to be made by theinfusion system. The system may also have a user readout display, whichdisplays parameters including, but not limited to, fluid temperature,line pressure, fluid flow rate, total volume of fluid infused, andtrouble alerts such as “air in line”, “overtemperature”, and“overpressure”.

In a preferred embodiment, the rapid infusion system can be powered byeither A.C. or D.C. current. If powered by D.C. current, standardbatteries can be used, including rechargeable batteries.

The rapid infusion system described herein can optionally infuse fluidsand measure C.V.P. through a single central venous catheter. The devicenot only infuses fluid and monitors C.V.P., but the device canoptionally adjust the flow rate automatically to achieve a programmedlevel of C.V.P. The device not only insures the ideal infusion rate forany particular patient but also-is an inexpensive alternative to large,expensive C.V.P. monitors and obviates the need to place a second venouscatheter dedicated only to C.V.P. readings.

The present invention can include a dial to set the desired C.V.P., ascreen that displays the actual C.V.P., and an assembly that stops thepump at preset time intervals in order to accurately measure the C.V.P.The operator need only select how often the pump should stop, read theC.V.P., and adjust the flow rate accordingly. The system can alternatelyinclude feedback mechanisms to read the C.V.P. and adjust the flow rate.A manual mode is provided to infuse at a simple fixed rate with a switchthat will halt the pump and give the operator an instantaneous C.V.P.reading. A pressure controller may be optionally used which maintainsthe C.V.P. within a preset range. The adjustable pump responds tosignals from the pressure controller and increases or decreases thefluid pressure and/or flow rate in response thereto. Similarly, thepresent device can incorporate other in vivo physiologic monitoringdevices to allow automatic regulation of infused fluids or medicationswithin pre-programmed parameters. Advantageously, the device has analarm indicating when the IV fluid bag(s) are nearly empty.

The invention is illustrated by the Figures and the followingdescription of a particular embodiment that is not to be construed inany way as imposing limitations upon the scope thereof. On the contrary,it is to be clearly understood that resort may be had to various otherembodiments, modifications, and equivalents thereof, which, afterreading the description herein, may suggest themselves to those skilledin the art without departing from the spirit of the present invention.

The system includes a pump that is driven by a pump drive assembly. Thepump is preferably a roller head occlusive pump. The rotating action ofthe pump roller head assembly imparts a directional, peristaltic motionto fluid that is contained within the pump chamber, which is preferablya section of collapsible tubing. The pump chamber is contained in aninfusion pump cartridge which also includes a drip chamber. The systempreferably includes a fluid self leveling system to keep the fluid inthe infusion pump cartridge at an appropriate level for more efficientpumping action. Before the fluid leaves the infusion system and entersthe patient, an optional heater module brings the pre-infused fluid tonear body temperature. In one embodiment, an electronic control systemmay be included which serves to operate the system within certainparameters that may be programmed beforehand, and is also capable ofmonitoring some physiologic factors and making programmed changes in theinfusion rate based upon those factors. A power supply provides thenecessary power. The power source can be either AC or DC. The infusionsystem can also be operated with power from an internal battery andincludes a connection jack for attachment of an auxiliary battery.Finally, the system may employ an adapter for affixing the device onto asupport stand while it is in use.

One embodiment of the infusion system is illustrated in FIG. 1, wherethe infusion system 100 includes a housing 115 with power cord storagebrackets 120 to receive any excess A.C. power cord during use. Thehousing further encloses a pump drive assembly 200, a pump roller headassembly 300, a disposable infusion pump cartridge 400, an automaticself-leveling system 500, a heater module 600 containing a disposableheater cassette 610, an electronic control/display module 700, and asupport attachment assembly 900. The housing may also include one ormore handles to facilitate its transportation. Since the system isdesigned to be portable, it is desirable that it measure less than about24 inches in any dimension and weigh less than about thirty pounds.However, it should be understood that while the relatively small size ofthe unit is advantageous, it is not critical to the invention.

FIG. 2 shows the relationship between the drive assembly 200 and theroller head assembly 300 in one embodiment of the present system. Asdescribed hereinafter, the roller head assembly 300 is attached to thedrive shaft of the pump drive assembly 200. In this embodiment of thepresent invention, the roller head assembly 300 is semipermanentlyattached and can easily be removed for replacement or service.

FIG. 3 is an exploded view of the drive assembly 200 in one embodimentof the present system. The drive assembly 200 is the power core or drivetrain of this embodiment of the rapid infusion system 100. The driveassembly 200 includes a differential box assembly 205, a differentialassembly 220, a stepper motor assembly 280, a gear box assembly 290, agear box differential gasket 294, a high speed motor assembly 295, and abracket assembly 299.

The differential assembly 220 allows the present invention to achieve asmooth transition between extremely high and low speeds. Thedifferential assembly 220 provides for the attachment of a plurality ofmotors to a common drive output shaft. The high speed motor assembly 295and the lower speed stepper motor assembly 280 are attached to the sameoutput shaft 244 (see FIG. 2) by the differential assembly 220. Thedevice can include other motor assemblies that attach to or interactwith the drive shaft, such as an intermediate speed motor, for example.In an alternate embodiment, a smooth transition from slow to fast speedcan be achieved using a larger stepper motor controlled by a controller.

The differential assembly 220 fits inside the differential box assembly205 and is held in position by a snap ring 297. The gear box assembly290 and the differential assembly 220 fit together with the gear boxdifferential gasket 294 intervening between them. The stepper motorassembly 280 attaches to the differential box assembly 205 with aplurality of screws 296. The high speed motor assembly 295 attaches tothe gearbox assembly 290 with a plurality of screws 298. The bracketassembly 299 is attached to the gearbox assembly 290 with a plurality ofscrews 287. The bracket assembly 299 affixes the drive assembly 200 tothe inner surface of the base of the housing 115.

FIG. 4 is an exploded view that further details the assembly of thedifferential box assembly 205. The differential box assembly 205includes a differential box 206, a bearing 207, a plurality of spacers209, an RPM sensor 211, a spacer bracket 213, and a dowel pin 219. Thedifferential box 206 houses the differential and provides a base towhich other components are attached. The bearing 207 is received by aformed recess inside the wall of the gear box 291 (as shown in FIG. 12).The spacers 209 maintain proper alignment between the gearbox 291 andthe differential box assembly 205, and between the attachment of thebase of the differential assembly 220 to the inner surface of thehousing 115. The spacer bracket 213 is mounted onto the differential box206 by a plurality of machine screws 228. The RPM sensor 211 serves totrack the rotations of the roller head assembly 300, and is attached tothe spacer bracket 213 by one or more self tapping screws 217.

FIG. 5 is a cross sectional view detailing the differential assembly220. The differential assembly 220 reduces wear on parts that wouldotherwise be produced by shifting gears. This serves to widen the rangeof speeds without a change in gear position. The differential assembly220 includes a yoke assembly 222, a gear shaft assembly 240, a bearingplate assembly 250, a worm bevel gear assembly 258, one or more spidergear assemblies 264, a bevel gear 266, one or more curve washers 272,one or more Belleville washers 274, and a dutch bearing 276.

The yoke assembly 222 receives attachments from most of the componentsof the differential assembly 220 either directly or through the gearshaft assembly 240 that defines a central axis of the differentialassembly 220. The bearing plate assembly 250 encloses the yoke assembly222 within the differential box 206, as shown in PIG. 4.

FIG. 6 is an exploded view detailing the components of the yoke assembly222. The yoke assembly 222 is the output shaft and the outer structureof the differential assembly. The yoke assembly 222 includes a bearing226, a yoke 224, one or more pin shafts 230, one or more spring plungers232, and a roll pin 234. The bearing 226 is received into a slot in theyoke 224 and acts as the pilot bearing for the gear drive shaft assembly240 (not shown). A plurality of machine screws 228 are positioned aroundthe perimeter of the yoke 224. The machine screws 228 create magneticspots that disturb the magnetic field, allowing the RPM sensor 211 (FIG.4) to determine the rate of rotation of the shaft. The pin shafts 230are received into bores in the fingers of the yoke 224 and act as shaftsfor the spider gear assemblies 264 (not shown). The spring plungers 232are received into detent grooves in the roller head drive shaft 305 (notshown) on the roller head assembly 300 (not shown) and hold the rollerhead drive shaft 305 (not shown) in place. The roll pin 234 protrudesthrough the central axis of the output drive and interlocks with theroller head drive shaft 305 (not shown).

The gear shaft assembly 240 is further detailed in FIG. 7. The gearshaft assembly 240 includes a high speed drive shaft 244, and a highspeed worm gear 248. The worm gear 248 engages the worm on the highspeed motor 295 (not shown).

The bearing plate assembly 250 is further detailed in FIG. 8. Thebearing plate assembly 250 supports the gear shaft assembly 240 (FIG. 5)to prevent flexing. The bearing plate assembly 250 also encloses thedifferential box 206, as shown in FIG. 3. The bearing plate assembly 250includes a bearing plate 252, a bearing 254, and a clutch bearing 256.The clutch bearing 256 allows movement of the high speed drive shaft 244in only a single direction. The bearing plate assembly 250 also supportsthe bearing 254 that encircles and supports the gear shaft assembly 240(as shown in FIG. 5).

The worm bevel gear assembly 258 is further detailed in FIG. 9. The wormbevel gear assembly 258 transfers power from the low speed stepper motor282 to the differential assembly 220. The worm bevel gear assembly 258includes a worm bevel gear 260 and a bushing bearing 262. The worm part260 a of the worm bevel gear 260 engages the worm on the low speedstepper motor 295 (not shown), and the bevel part 260 b of the wormbevel gear is one of the four gears that make up the differentialassembly 220 (not shown). The bearing 262 presses into the center of theworm bevel gear 260 and allows the worm bevel gear 260 to spin freelyaround the gear shaft assembly 240 (not shown).

A spider gear assembly 264 is further detailed in FIG. 10. The spidergear assemblies 264 are two of the four gears that make up thedifferential. The spider gear assemblies ride freely on the gear shaftassembly 240 and transfer the force from the motors to the output shaft.Each spider gear assembly 264 includes a bevel gear 266 and a flangedbearing 268.

The stepper motor assembly 280 is the low speed drive, and itscomponents are detailed in FIG. 11. The stepper motor assembly 280includes a stepper motor 282, a worm gear 284, a shaft extension 286,and a bearing 288. The shaft extension 286 attaches to the output shaftof the stepper motor 282 with one or more set screws 289. The worm gear284 attaches to the shaft extension 286 with one or more set screws 289.The stepper motor assembly 280 attaches to the differential box 206 asshown in FIG. 3, and the worm gear 284 engages the worm gear 260 on theworm bevel gear assembly 258 of the differential (not shown). The wormgear 284 eliminates the possibility of back driving, which could resultin a loss of power. The stepper motor assembly 280 operates in a cycleof pulses, turning one step after each pulse.

Referring to FIG. 12, the gear box assembly 290 encloses and supportsthe gear shaft assembly 240 (not shown). The gear box assembly 290includes a gear box 291, one or more dowel pins 292, and one or morebearings 293. The high-speed motor assembly 295 attaches to the side ofthe gear box assembly 290 as shown in FIG.3, and the dowel pins 292further align the high-speed motor assembly 295. The bearing 293contacts the high speed worm 248 and further supports the gear shaftassembly 240 (not shown).

The high-speed motor assembly 295 is the high speed power source and isfurther detailed in an exploded drawing in FIG. 13. The high-speed motorassembly 295 includes a high speed motor 302, a motor mount flange 304,a high speed worm gear 248, a high speed shaft extension 244, and abearing 226. The high speed motor 302 is attached to the motor mountflange 304 by a plurality of machine screws 298. The high speed wormgear 248 is attached to the high speed shaft extension 244 by one ormore set screws 289. The high speed shaft extension 244 is attached tothe output shaft of the high speed motor 302 by one or more set screws289. The high speed worm gear 248 engages the worm gear 260 on the gearshaft assembly 240 (not shown). The motor mount flange 304 provides ameans for attaching the high speed motor 302 to the gear box assembly290.

When the stepper motor assembly 280 is running, the clutch bearing 256forces the bevel gear 266 to become stationary. When the high speedmotor assembly 295 is running, the stepper motor assembly 280 forces theworm bevel gear 260 to become stationary, and the bevel gear 266 and thegear shaft assembly 240 to rotate. The yoke assembly 222 rotates aroundwhichever gear is stationary at a given time, which is, in turn,determined by which of the motors is running at that time.

The mount plate assembly 235, as shown in FIG. 14 is the externallyvisible part of the pump drive assembly 200 to which the disposableinfusion pump cartridge assembly 400 attaches, as shown later. The mountplate assembly 235 includes a mounting plate 236, long mount pins 237,and short mount pins 238. The long mount pins 237, and short mount pins238 engage channels molded into the rear face of the rear cartridgeframe 410 to guide and secure the long mount pins 237, and short mountpins 238 in position for use.

The roller head assembly 300, as detailed in FIGS. 15 and 17, is thedrive part of the pump assembly. The roller head assembly 300 includes aroller head drive shaft 305, pivot arm assemblies 310, spacers 320, aroller cover bottom 325, a roller cover top 330, Teflon washers 335, asnap ring 340, cap screws 345, and lock washers 350. The pivot armassemblies 310 extend and retract the rollers on the roller head driveshaft 305. In one embodiment of the infusion system, the roller headdrive shaft 305 can be designed so that it is removable for replacementor service. Optionally, the roller head assembly 300 may easily beremoved from the pump assembly for cleaning or replaced altogether foreasier service. The roller head assembly preferably includes two rollersset about 180° apart to maximize filling of the pump chamber duringoperation. However, the assembly can include more than two rollers.

As shown in FIG. 16, each pivot arm assembly 310 includes a pivot gear311, a roller 312, a stop pin 313 and a pivot pin 314. The pivot armassemblies 310 hold the rollers 312 that ultimately contact the pumpingchamber (shown as soft pump tubing 415 in FIG. 19), and impartperistaltic pumping motion to the fluid within the pump tubing 415. Thepivot gears 311 on the pivot arm assemblies 310 engage with the gear onthe roller head drive shaft 305.

The roller head assembly 300 is received by the output shaft 244 of theyoke 220 in the pump drive assembly 200 (as shown in FIG. 2). As theroller head drive shaft 305 turns in one direction, the pivot arms 310are forced to turn in the opposite direction on the pivot pin 314. Thisoutward rotation of the pivot arms 310 is controlled by the stop pins313. Thus, the pivot gears 311 and the roller head drive shaft 305rotate as a unit. As the roller head drive shaft 305 turns, the rollers312 roll along the pump tubing 415 (see FIG. 19) with the compressionaction of the rollers 312 causing fluid to move through the pump tubing415.

Once the rollers extend to compress the tubing at a predictable tension,rotational motion of the entire roller head assembly ensues. This inturn causes peristaltic compression of the pump tubing thus impartingmotion to the contained fluid. Once the rollers 312 are extended, therotary motion of the roller head assembly 300 compresses the pump tubing415 with a consistent, predictable tension level on each revolution.

Assembled portions of the roller head assembly are further illustratedin FIG. 17. The relationship between the roller head assembly 300 andthe disposable infusion pump cartridge 400 are shown in a posteriorperspective in FIG. 18B.

Portions of the fluid containment system are illustrated in FIGS. 18Athrough 20. The fluid containment system includes a drip chamber and apump chamber that are preferably assembled together in a disposable pumpcartridge. The fluid containment system further includes IV tubing thatdirects infusium from one or more fluid reservoir(s) to the dripchamber, and an output infusion line that directs infusium from the pumpto the patient. The fluid containment system can further include aheater cartridge, as described below.

The IV tubing system used in one embodiment of the rapid infusion system100 is shown in FIG. 18A. The IV line assembly 800 carries fluid fromthe fluid reservoir(s), such as standard IV fluid bags or bloodcontainers (not shown), to the infusion pump cartridge 400. In arepresentative embodiment, the IV line assembly 800 includes a maintubing line 805, one or more pinch clamps 810, a main blood spike 815,one or more female Luer locks 820, one or more male Luer locks 825, aY-connector 830, one or more in-line drip chambers 835, one or moreauxiliary blood spikes 845, one or more auxiliary tubing lines 850, oneor more sections of tubing 855, a flow control pinch valve 860, and afilter 865.

The main spike 815 is inserted into the primary fluid reservoir. Whenthe main spike 815 is not inserted into the reservoir, the main bloodspike 815 is covered with a spike cap (not pictured). The fluid thenflows from the fluid reservoir into the main tubing line 805. A flowcontrol pinch valve 860 on the main line 805 allows the operator tocontrol the rate of flow in relation to the other lines. The main line805 then connects into a Y-connector 830 that provides for two auxiliarylines 850. Each auxiliary line 850 has a pinch damp 810 that can beopened or closed to keep fluid from flowing prematurely through theline. Luer locks 820, 825 connect each auxiliary line 850 to a sectionof tubing 855 which fastens to an in-line drip chamber 835. The in-linedrip chamber 835 allows the operator to visually monitor the rate offlow. Inside each in-line drip chamber is a filter 860. The filters 860prevent contamination and the passage of clots or other material thatmay occur in stored fluid.

Directly above each in-line drip chamber 835 is an auxiliary blood spike845 for spiking auxiliary fluid reservoirs. Spike caps (not pictured)cover the auxiliary spikes 845 when not in use. The Y-connector 830connects the main tubing line 805 and the auxiliary tubing line(s) 850with a common input tubing 840 which connects to the pump tubing inletport 425 of the disposable infusion pump cartridge 400 (See FIG. 18B.)

The infusion pump cartridge 400 includes a drip chamber and receivesfluid from an external fluid reservoir. The infusion pump cartridge 400mounts on the front of the rapid infusion system 100, such that theinfusion pump cartridge 400 can interact with the infusion pump assembly200 (FIG. 18B) and the automatic self-leveling system 500 (discussedbelow). Other embodiments of cartridges can alternatively be used in thepresently described system.

FIGS. 19 and 20 are exploded views that detail the components of oneembodiment of the infusion pump cartridge 400. The cartridge includes afront cartridge frame 405, a rear cartridge frame 410, and a formed pumptubing 415 which serves as the pump chamber, with retention flange 416.The cartridge further includes a drip chamber 420, a pump tubing inletport 425 (FIG. 20) receiving the intake end of the pump tubing 415, apump tubing outlet port 430 (FIG. 20) receiving the outlet end of thepump tubing 415, a vent cap 465 containing a central punctuate aperture466, a vertical optical chamber 470, internal outlet tubing 475 and adrip chamber top 435.

As further shown in FIG. 19, the front cartridge frame 405 and the rearcartridge frame 410 contain a plurality of upper holes 412 and lowerholes 414, which serve to fix the assembled cartridge 400 to the shortmount pins 238 and the long mount pins 237, respectively on the mountplate assembly 235 during system operation.

The pump tubing 415 is preferably molded from silicone or a similarsoft, pliant material. The pump tubing 415 can have a variety of shapes,such as circular, semicircular, “U”, or “Ω” shaped curve, with the innercurve sized and shaped to maximize the pumping action from contact withthe roller head assembly 300 (see FIG. 18B). In the embodimentillustrated, the pump tubing 415 is “U” shaped, but contains a spacer419 at the upper pole of the curved tubing channels that serves to forma complete, 360° contact surface to provide constant resistance when theroller head assembly 300 interfaces with the pump tubing 415. The pumpchamber is preferably tightly attached to the frame to prevent movementor dysfunctional deformation of the pump chamber during pumping. In theembodiment illustrated, the outer curve of the pump tubing 415 containsa retention flange 416 (FIG. 19), which is tightly retained within thefront cartridge frame 405 and the rear cartridge frame 410 when thedisposable infusion pump cartridge is assembled. The retention flangefurther contains a plurality of holes 417 that are retained by aplurality of symmetrically arranged retention pins 418 on the cartridgeframe. The pins can be in the rear cartridge frame 410 as shown and canbe retained by a plurality of matching indents (not visible) in thefront cartridge frame 405.

The remaining elements of the infusion pump cartridge 400 are preferablyfabricated of rigid plastic, such as PVC or polystyrene, for example.The front cartridge frame 405 and the rear cartridge frame 410 arebonded together during assembly, along with the pump chamber, the dripchamber 420, and the drip chamber top 435. The drip chamber top 435 isreceived by and retained by a friction fit within the drip chamber 420by an inner flange (FIG. 20).

As shown in FIG. 18B, the pump tubing 415 connects to a drip chamber 420through a pump tubing inlet port 425, and a pump tubing outlet port 430.The drip chamber top 435 further includes an inlet port 445 and anoutlet port 446. The inlet port 445 and outlet port 446 are integralextrusions from the upper surface of the drip chamber top 435. The inletport 445 on the drip chamber 420 receives the infusion fluid fromexternal fluid reservoir through conventional or modified I.V. tubing,and allows passage of the infused fluid into the interior of the fluidwell 420. The outlet port 446 connects to the output infusion line (notshown). This output line can transfer blood to the heater (as discussedbelow) or directly to the patient.

The fluid containment system, including IV tubing 800, infusion pumpcartridge 400, and output infusion line 880 can be assembled andsupplied as one unit. The heater cassette 610, as discussed below, canalso be assembled in this unitary assembly. In this way, all of thefluid contacting elements can be preassembled and sterilized.Complications such as delay and contamination can thus be avoided. Thedrip chamber 420 can have a volume of about 20 to over 500 cubiccentimeters (cc). The drip chamber 420 (FIGS. 20-21) has a sloping floor421 from the outlet port 430 to the inlet port 425 to facilitate fluidflow out of the drip chamber 420. The inlet port 445 on the drip chamberis preferably connected-to a diversion tube 422 that curves to deliverthe fluid to the surface of the upper portion of the sloping floor 421.The diversion of the incoming fluid through the diversion tube 422reduces the formation of air bubbles in the fluid and the possibility ofadditional hemolysis from cellular trauma that might result from a freefall of the fluid into the drip chamber 421. The pump tubing inlet port425 and pump tubing outlet port 430 are integral extrusions from thelower surface of the fluid well 420. The central lumen of the pumptubing inlet port 425 freely connects with the interior of the fluidwell 420. The pump tubing outlet port 430 connects with a rigid internaloutlet tubing 475 that connects vertically with the outlet port 446 inthe drip chamber top 435.

To minimize inadvertent air trapping within the system, the inlet port445 in the drip chamber top 435 is preferably vertically offset from thepump tubing inlet port 425. Fluid cannot, therefore, drop directlythrough the fluid in the drip chamber into the pump tubing in the courseof operation. Alternatively, or in addition, a baffle can be placedabove the pump tubing inlet port 425 to deflect the inlet stream awayfrom the inlet port 425 so that air bubbles do not enter the inlet port425.

The drip chamber top 435 further contains a plurality of conicalperforations 440 with rounded edges in their smaller openings in theupper surface of drip chamber top 435, for purposes as described below.The conical perforations 440 serve to allow the egress of air from thedrip chamber 420 during auto-leveling, yet reduce the likelihood of aningress of fluid into the pump responsible for purging air. The conicalperforations 440 are covered by a filter 455, preferably hydrophobic, tofurther prevent fluid from entering the air purge pump, an 0-ring 460,and a vent cap 465 which secures by a friction fit over the formed ring450 in the upper surface of the drip chamber top 435. The height of theformed ring 450 in the upper surface of the drip chamber top 435 may bealtered to maximize the efficiency of the automatic self-levelingsystem.

The infusion system preferably includes an automatic fluid self-levelingsystem that is designed to keep the cartridge drip chamber at anappropriate fluid level to facilitate the overall pump operation. Theself-leveling system also serves as an air removal system to reduce thepossibility of air embolism from inadvertent ingress of air bubbles intothe infused fluid. The self leveling system includes a fluid levelsensor to determine the level of fluid in the drip chamber and a fluidlevel controller to automatically fill the drip chamber to the desiredlevel.

An optical chamber 470 extends from the rear surface of the drip chamber420. The optical chamber contains a central lumen that is contiguouswith the lumen of the drip chamber 420. The optical chamber 470 is amolded extension of the fluid well 420 and is preferably fabricated withtransparent walls of optical quality.

FIGS. 21 and 22 illustrates an automatic self-leveling system 500 andits relationship with the disposable infusion pump cartridge 400. Asdescribed above, the infusion pump cartridge 400 contains an integraloptical chamber 470 that is continuous with the chamber. The opticalchamber 470 is physically raised from the back surface of the dripchamber 420. When the disposable infusion pump cartridge 400 is insertedinto the infusion pump assembly 100, the optical chamber 470 is alignedwith a detector board 505 that is mounted vertically in a recess in thefront of the housing 115. The detector board 505 is connected to aplurality of transmitters and detectors 515, preferably between five andten, including sensors and transmitters 510. The sensors are preferablyinfrared sensors but can be other types of sensors, such as light orlaser sensors or ultrasonic sensors.

A diaphragm pump 530 is mounted to the inner aspect of the housing 115by a plurality of machine screws (not shown). Alternatively, thediaphragm pump can be placed at a distance from the housing with aconnecting tube. The diaphragm pump 530 is an electrically powereddiaphragm pump or any other pump that can exert a negative pressure. Thediaphragm pump 530 contains a tubular interface 520 which connects tothe intake port of the diaphragm pump 530. The diaphragm pump interface520 further makes a friction fit over the vent cap 465 on the top of theinfusion pump cartridge 400, when the cartridge is placed into itsoperational position within the rapid infusion system 100. The diaphragmpump 530 further includes a check valve (not illustrated) placed in anoutlet line of the diaphragm pump 530 to reduce the possibility of airentering the drip chamber when the diaphragm pump 530 is inactive.

When the sensors 510 indicate that the fluid level within the opticalchamber 470, and thus the drip chamber 420, has gone below a certainlevel, the diaphragm pump 530 is automatically activated and extractsair through the aperture in the vent cap 465 in the fluid well top 435(FIG. 22). This creates a self leveling drip chamber to keep the fluidwell 420 at an appropriate fluid level, with the resulting increase inpump efficiency. This has the effect of removing air that could bepotentially embolic and detrimental to the patient's health. Desirably,the drip chamber stays at least 50% filled with infusion fluid,preferably at least 75% filled. The infusion system includes a shut offswitch that will stop the pump if the fluid level in the drip chamberfalls below a certain level, such as about 5% full, for example.

In another embodiment of the fluid level controller (not illustrated), acap on the drip chamber can be opened automatically or by the operatorto release air from the drip chamber. The pump is stopped to stop flowof fluid from the drip chamber. However, fluid continues to flow intothe drip chamber from gravity and replaces air in the drip chamber untilthe fluid level is back to the desired range. The cap is then replacedand the pump resumed.

In another embodiment of the fluid level controller (not illustrated),the optical chamber 470 contains a small float that allows enhancedsensing of the fluid level by the sensors 510.

When large volumes of fluid are to be infused into a patient, it isadvantageous to heat the fluid to body temperatures before infusion tominimize any thermal insult during infusion. One embodiment of a heatermodule 600 is illustrated in FIG. 23. The heat module assembly 600includes a right heater block 620, a left heater block 630, and a heaterpower board 670. Fluid from the pump flows from the pump cartridge 400and into a separate, preferably disposable, heater cassette 160. Theheater cassette can be modular and can be attached when needed. Enteringat the bottom of the cassette 610, the fluid flows through a channeledinternal pathway within the cassette 610 between the heater blocks 620,630. The fluid is heated as it passes through the cartridge and thefluid exits through the distal end of the heater module 600. Having thefluid enter from the bottom and exit from the top further ensures thatair is purged from the heater cassette. Each heater block includes ametallic plate 625 that covers an electric heating element 628. Fluidtemperature and pressure within the heater module 600 are monitored byin-line thermal sensors 640 and pressure sensors 650. After the fluidfinally exits the heater module 600, the fluid is monitored by sensors660 to check for air bubbles before the fluid enters the patient throughthe output infusion line 880. Alternatively, the system can include anair bubble sensor in the outlet infusion line. Signals from the thermalsensors 640, pressure sensors 650, and air bubble sensors 660 areconveyed to the system's electronic control system for analysis andinitiation of any necessary corrective or warning actions.

Alternative embodiments of the heater module 600 include use of a singleheating element, use of three or more heating elements, use of areflector to deliver additional heating function from the heatingelement(s), use of a linear or linear matrix fluid path instead of achanneled course, and/or use of a heated bath to provide the warmingfunction. Energy sources that can warm fluids can include microwave orradiant heat sources.

A pole clamp assembly 900, shown in FIGS. 24A and 24B, and serves toattach the infusion system 100 or other system to an IV pole or similarvertical support member. The pole clamp assembly 900 works like a riflebolt to clamp the infusion device or other system to a pole and securelylock it in place. The pole clamp assembly 900 accommodates a range of IVpole sizes from less than 1/2 inch to over 3 inches in diameter. One ofthe advantages of the pole clamp assemble is that, in one motion, theuser can attach the device and lock it into place on poles of differentdiameters. The pole clamp assembly 900 includes an extrusion 910, aplurality of bumpers 920, and a pole clamp slide assembly 930.

The pole clamp slide assembly 930 further includes a shaft 935, a collar940, a bumper 945, a handle, 950, a dowel pin 955, a wedge 960, a lowerblock 965, a hex nut 970, a knob 975, an upper block 980, and a spring985. The pole clamp slide assembly 930 is the sliding piece that adjustsfor and locks the infusion pump system to various sizes of IV or othersupport poles. The upper block 980 and lower block 965 contain a troughalong their long axes that is sized to receive the shaft 935, thusholding the shaft 935 between the upper block 980 and lower block 965.The troughs of the upper block 980 and lower block 965 each provide acomplimentary locking track, sized to receive the collar 940. The collar940 goes over the shaft 935 and is guided into the locking tracks 990 bythe dowel pin 955. The bumper 945 allows resilience at the end of theshaft and prevents marring of the support pole surface.

As the collar 940 rotates in the locking track 990, the wedge 960 ispushed inward and engages with the shaft 935. There are serrated teethon the shaft 935 that engage teeth on the wedge 960. When the teethlock, the entire pole clamp assembly 900 moves towards the pole. Thespring 985 keeps the teeth on the wedge 960 from engaging in the processof making a gross adjustment. The extrusion 910 wraps around the IVpole, and the bumpers 945 provide a non-slip surface and prevent marringof the pole. Gross adjustments may be made by lifting the handle 950 upand sliding it forward. This action moves the pole clamp slide assembly630 towards the pole. Turning the handle 950 downward locks the clampinto place.

FIG. 25 is a block diagram illustrating an electronic control system2600 of an exemplary embodiment of the present invention. The electroniccontrol system 2600 employed in this embodiment serves to perform suchfunctions as: regulating the pump drive assembly 200 and the heatermodule 600; monitoring and operating the automatic self-leveling system500; communicating with physiologic monitoring devices and appropriatelyadjusting the pump function in response to physiologic factors; andcommunicating with medical personnel via user interface control/displaypanel 700. These and other functions of the present invention arecontrolled by the electronic control system 2600. It should beunderstood that the components forming the electronic control system2600 may be conventional components that are well known in the art.

A processor 2602 is provided for executing software and/or firmwarestored in memory 2604, which controls the operation of the infusion pumpsystem 100 of the present invention. By way of example, firmware may bestored in read only memory (ROM) 2606 and software may be stored inrandom access memory (RAM) 2608. Other types of memory storage devicesmay be provided, such as such as magnetic cassettes, flash memory cards,digital video disks (DYD), Bernoulli cartridges, EPROM, EEPROM, or anyother type of computer-readable media. As is well known in the art,software is generally programmable and reprogrammable. Therefore, viavarious user interfaces, the user may be provided with the ability toprogram and re-program the operating parameters of the infusion pumpsystem 100.

The processor 2602 of the electronic control system 2600 communicateswith the various sensors of the infusion pump system 100 by way ofvarious corresponding interfaces. For example, an exemplary electroniccontrol system 2600 may include a RPM sensor interface 2610 whichfacilitates communication between the processor and a RPM sensor 211 formonitoring the speed of the pump drive assembly 200. The exemplaryelectronic control system 2600 may also include an infrared sensorinterface 2612, a temperature sensor interface 2614, an ultrasonicsensor interface 2616, and an air pressure sensor interface 2620 forfacilitating communications between the processor 2602 and an infraredsensor 510, a temperature sensor 710; an ultrasonic sensor 725, and apressure sensor 730 respectively. As mentioned previously, thetemperature sensor and the pressure sensor may be used to monitor thetemperature and the pressure, respectively, of the fluid as the fluidleaves the infusion pump system, while infrared sensor(s) and ultrasonicsensor(s) or other sensors may be used to detect air bubbles and otherimpurities.

The processor 2602 can transmit data to a remote location such asthrough a telephone or other data line. The processor 2602 can alsoreceive data and instructions from a remote location.

The processor 2602 also communicates with the various electromechanicalcomponents of the infusion pump system 100 via various correspondinginterfaces. By way of illustration, the electronic control system 2600may include a diaphragm pump interface 2622, a motor interface 2624, aheater interface 2626, a fan interface 2630, and an alarm interface2632. The electronic control system 2600 may also include acontrol/display interface 2634 for facilitating communication betweenthe user control/display panel 700 and the processor 2602 and one ormore I/O port interfaces 2636 for facilitating communication between theprocessor 2602 and various devices that may be received via input/outputports. The electronic control system 2600 may further include a powersupply interface 2640 for facilitating the supply of power to theprocessor 2602.

By communicating with the various sensors and the variouselectromechanical components of the infusion pump system 100 and byexecuting appropriately programmed software and/or firmware, theprocessor 2602 may be operable to automatically control the operation ofthe infusion pump system 100. For example, the processor 2602 mayreceive a user instruction from the control/display panel concerning adesired rate of fluid infusion. In response to the user instruction, theprocessor 2602 may interact with the RPM sensor interface 2610 in orderto determine the rate of the pump drive assembly 200. In response todetermining the rate of the pump drive assembly 200, the processor 2602may interact with the motor interface 2624 in order to increase ordecrease the speed of one or both of the stepper motor assembly 280 andthe high speed motor assembly 295. The processor 2602 may also beoperable to interact with the control/display interface 2634 in order todisplay the rate of the pump drive assembly 200 to the user on thecontrol/display panel 700. The processor 2602 may be further operable toactivate the fan 720 for the purpose of cooling the pump drive assembly200, if the RPM sensor 211 indicates that the pump drive assembly 200exceeds a particular rate.

As another example, the processor 2602 may be operable to maintain agiven temperature for the fluid in the pump tubing 115 by interactingwith the temperature sensor interface 2614 and the heater interface2626. The given temperature may be a pre-determined default value or maybe set by the user via the control/display panel 700 and communicated tothe processor 2602 via the control/display interface 2634. In responseto continuous temperature readings detected by the temperature sensor710, the processor 2602 may be operable to adjust the heat output of theheater module 600 accordingly. Likewise, the processor 2602 may beoperable to receive a signal from the infrared sensor interface 2612 orthe ultrasonic sensor interface 2616 or other sensors indicating thepresence of an air bubble or other impurity in the pump tubing 415. Inresponse to an impurity signal, the processor 2602 may be operable toengage the diaphragm pump 530 for removing the impurity from the pumptubing 415. If an impurity signal persists, the processor 2602 maycommunicate with an alarm 705 via the alarm interface 2632 forgenerating a warning signal to the user. The processor 2602 may also beprogrammed to automatically power down the pump drive assembly 200 inresponse to undesired temperatures of the infusion fluid or persistentimpurities in the pump tubing 415.

As a further example, the processor 2602 may be operable to communicatewith other digitally-controlled machines or medical instruments via theI/O port interface(s) 2636 in order to receive patient measurements,such as the central venous pressure or other physiologic or chemicalconditions of the patient. As such, any well known digitally-controlledmachine or medical instrument may be integrated into, or operated intandem with, the infusion pump system 100. The processor 2602 may beprogrammed to appropriately adjust the operation of the infusion pumpsystem 100 in response to patient measurements.

All data signals received by the processor 2602 via a sensor interface,an I/O port interface 2636, or the control/display interface, may betranslated into user readable symbols and displayed on thecontrol/display panel 700 and/or may be stored in memory 2604.Accordingly, the processor 2602 may be programmed to retrieve data frommemory 2604 and to perform calculations thereon. Such calculations maybe specified by the user via the control/display panel 700 or may bepredetermined default calculations. The processor 2602 may further beoperable to display the results of such calculations on thecontrol/display panel 700.

FIG. 26 shows an electronic control/display user interface panel 700 inone exemplary embodiment of the rapid infusion system. In this example,the upper portion of the control/display array is for routine orstandard infusion rates. The lower portion of the control/display arrayis for rapid infusion.

The rapid infusion system can optionally include a fluid rate titratorto allow the user to titrate from a standard rate to a rapid rate, inthe event that rapid infusion is subsequently needed during treatment orsurgery. In the illustrated embodiment the titrator is a voltage controlcircuit 765 used to regulate the voltage across the pump drive assembly200. The user presets a rapid infusion rate. Activation of a single“Rapid” switch 770 unlocks a dial on the spring-loaded potentiometer andplaces the voltage control circuit 765 in series with the pump driveassembly 200. The user can then use the voltage control circuit 765 tovary the voltage applied to the pump assembly 200 to regulate the rateof increase of the flow rate. For example, the voltage control circuitcan be a simple potentiometer, or variable resistor. When the useractivates the “Rapid” switch, the potentiometer is enabled. The userregulates the voltage increase across the pump drive assembly 200 byadjusting the potentiometer dial. As the user increases the rotation ofthe potentiometer dial, the voltage across the pump drive assembly 200increases. The increase in voltage is directly proportional to thedegree of rotation of the dial. For example, if the standard infusionrate is set at 300 cc per hour and the rapid infusion rate is set at1000 cc per minute, turning the potentiometer dial half way between theminimum and maximum positions would increase the infusion rate to 497.5cc per minute.

The rate at which the voltage increases across the pump drive assembly200 is directly proportional to how “fast” the user rotates the dial.Using the above example, if the user slowly turns the dial from the 300cc setting to the 1000 cc setting, the rate at which the flow rateincreases is also very slow. If, however, the user rotates thepotentiometer dial very quickly, the infusion rate will increase from300 cc per hour to 1000 cc per minute almost instantaneously. Thereforeit is up to the user to manually regulate how fast the infusion rateincreases from the normal setting to the final setting. Once the userreleases the dial, the spring retracts and returns the potentiometerdial to its initial setting and the pump returns to the standardinfusion rate in another example, the voltage control circuit 765 may bean infrared detector (IRD) coupled to a bank of light emitting diodes(LEDs). The output of the IRD is connected to the pump drive assembly200. To apply a voltage to the pump drive assembly 200, the useractivates at least one LED. The incident light upon the IRD creates avoltage at the output terminals of the IRD. To increase the outputvoltage, the user simply increases the amount of light incident upon theIRD. This may be accomplished by simply turning on additional LEDs.

To activate the LEDs, a spring-loaded dial may be placed in proximity tothe leads of the LEDs. As the dial is rotated, it comes in contact withthe leads of LEDs and forms a closed circuit causing the LEDs to light.As the dial is rotated farther, it contacts the leads of more LEDs,thereby increasing the amount of light falling on the IRD, and thusincreasing the output voltage. However, each LED emits a discrete amountof light. Therefore, the increase in the output energy will in steppedup by discrete values. To remove these step variations, and ensure thatthe increase in flow rate is gradual, the output voltage may be passedthrough a low-pass filter before it is applied to the pump driveassembly 200.

Although the voltage control circuit 765 has been described in terms ofa potentiometer and an IRD circuit, those skilled in the art willappreciate that other voltage control circuits may be substituted forthose devices in the preferred embodiments without altering the scope ofthe invention.

A jack 775 on the display panel 700 offers a connection for an optionalfoot or hand control for the rapid infusion system. The optional foot orhand control would serve the same purpose as the potentiometer, with theadded benefit of allowing the operator to work while moving around and,with the foot control, hands free.

Electrical power to the pump drive assembly 200, the automaticself-leveling system 500, the heater module 600, the electronic displaysystem 700, the electronic control system 2600, and other parts isprovided through the system power supply 2700 (not shown). The powersupply 2700 derives its power either from external A.C. line current orfrom internal D.C. batteries. Standard circuitry is employed to connectthe power source(s) through one or more standard transformers and thenfor delivery within the system. External batteries can also be used.

In addition, the power supply serves an electric cooling fan 720 ofstandard design, with the fan being mounted on or within the internalaspect of the system housing 115 (not shown). The cooling fan 720 isemployed to reduce internal heat from the motors 280,295, heater module600, diaphragm pump 530, and system electronics 2600. Operationalswitching and regulation of the fan 720 are optionally controlled by oneor more thermal sensors 750 within the rapid infusion system 100.

Operation

The rapid infusion system can be operated as a low-speed infusion devicefor routine IV infusion. The infusion system can also be operated as ahigh-speed infusion device for rapid infusion of fluids to a traumavictim in an emergency room, at an accident scene, or in an ambulance,for example. The device can be particularly advantageous in situationswhere it may be preferable to first employ routine IV infusion followedby rapid infusion, followed again by routine infusion, such as during atransplant operation, for example. The device can be operated at ratesranging from less than 20 cc per hour to greater than 1.2 liters perminute and allows seamless transition of infusion rates.

The rapid infusion system is powered up by toggling a main power switch.If the unit is connected to a live AC power source, then the system willoperate on AC power. If there is no AC power connection, or if AC poweris interrupted, the system will automatically use its internal batteryDC source. Residual battery power is monitored by the electronic controlsystem during use, and user warnings are provided when battery strengthis waning.

Conventional IV fluid or blood bags or bottles can be used, for example,or an alternate fluid reservoir can be employed, particularly when largequantities are to be infused. The bags or bottles are spiked with adelivery tubing that is connected to a disposable rapid infusion pumpcartridge. The cartridge is inserted in the front of the infusionsystem, with the pump roller head in position in the center of theseated cartridge.

The holes in the cartridge frame then are placed over the correspondingposts on the mounting plate face, which hold the cartridge securely inposition during pump operation. The load button is then activated toextend the rollers.

The user may program the system to deliver a set volume of infusedfluid, at a selected infusion rate. Other control options includespecifying certain target parameters such as C.V.P., when the system isequipped to monitor such functions.

If the user believes that rapid infusion might be needed, the user maypreset a rapid infusion rate in the event there is a clinical need forthis function. When the rapid infusion system is employed for routine IVinfusion, the user has the option of pre-setting a rapid infusion ratein the event that a clinical need for this function arises. A springpotentiometer can be instantly triggered and activated by toggling asingle “Rapid” switch if this operation is suddenly required. Activationof the potentiometer allows the operator of the present invention totitrate the fluid rate to the patient from the routine rate up to apreset rapid rate.

Generic defaults for rapid rate and infusion volume settings areoptionally programmed into the system, should a need arise before userselected values have been entered.

Additional controls allow for one button bolus administration, alongwith various monitoring functions. The system automatically monitors thefluid level in the drip chamber, and will engage a diaphragm pump toremove air if the fluid level gets too low. The system willautomatically turn off the pump and alert the user if air bubbles arepresent in the outgoing tubing.

The heater module employs an additional disposable cartridge that isconnected in-line with the infusion fluid to warm the fluid to bodytemperature before infusion into the patient. Additional electroniccontrols monitor both the temperature and pressure of the fluid as itexits the heater module.

When infusion has been accomplished, the disposable infusion pumpcartridge may be removed from the device and discarded. The operatorpresses the “Load/ Unload” button, which causes the rollers in the pumphead to retract, facilitating the cartridge removal, and protecting theroller mechanism.

If necessary for either cleaning or system maintenance, both the pumproller head unit and the roller head drive shaft may be readily removedand cleaned or replaced. All portions of the rapid infusion system thatdirectly contact the infusion fluid are designed for sterile, single useand do not require cleaning.

Unlike standard or traditional methods of intravenous fluidadministration, the rapid infusion system described herein can providecontinuous total replacement of adult human blood volume throughvirtually any sort of hemorrhage, for an indefinite period of time andcan rapidly regulate fluid temperature with minimal increase inresistance to flow, easily and rapidly administer massive quantities ofblood to a single patient during a single operation, administerphysiologic fluid maintained at a predetermined temperature at flowrates in excess of 1500 cc/minute, and permit simultaneous display andcontrol of fluid temperature. The system can easily be carried and isable to be quickly and easily used in emergency situation or byemergency personnel in the field. The blood delivered by the system caninclude clotting factors and can infuse an infinite amount of blood overan indefinite period of time based on the pump assembly employed, thetubing sizes, etc., employed.

If desired, the present invention can include multiple pumps infusingfluid to a patient through multiple catheters, thereby providing suchfluids to the patient in volumes which are far exceed that possible bypresent infusers.

While the system is described herein as applicable for fluid infusion,it should be understood that the system can also be used for otherpurposes such as a surgical irrigation system or for autotransfusion ofblood from a chest tube or cell saver.

The above description is intended to be illustrative and notrestrictive. Many embodiments will be apparent to those of skill in theart upon reading the above description. The scope of the inventionshould therefore be determined not with reference to the abovedescription, but should instead be determined with reference to theappended cairns, along with the full scope of equivalents to which suchclaims are entitled. The disclosures of all articles and referencesreferred to herein, including patents, patent applications, andpublications, are incorporated herein by reference.

1. A rapid infusion system for delivering infusium into a patientcomprising: a. an infusium tubing; b. means for imparting motion toinfusium by contact with the infusium tubing; c. a differential outputshaft assembly comprising: i. an output shaft in communication with themeans for imparting motion to the infusium; ii. a differential assemblyin mechanical communication with the output shaft; iii. a first speedmotor assembly in mechanical communication with the differentialassembly; and iv. a second speed motor assembly in mechanicalcommunication with the differential assembly.
 2. The rapid infusionsystem of claim 1, wherein the means for imparting motion to theinfusium is a roller pump head.
 3. The rapid infusion system of claim 2,wherein the roller pump head comprises two pivot arm assemblies.
 4. Therapid infusion system of claim 3, wherein the two pivot arm assembliesare mounted on the roller cover 180 degrees apart.
 5. The rapid infusionsystem of claim 3, comprising more than two pivot arm assemblies.
 6. Therapid infusion system of claim 1, wherein the system is capable ofdelivering infusium to a patient at rates of between 20 cc/hour to 1,500cc/minute.
 7. The rapid infusion system of claim 1, wherein the firstspeed motor is a stepper motor.
 8. The rapid infusion system of claim 1,wherein the second speed motor is capable of operating the output shaftat a faster rate than the first speed motor.
 9. The rapid infusionsystem of claim 1, further comprising a third speed motor in mechanicalcommunication with the differential assembly.
 10. The rapid infusionsystem of claim 1, further comprising a controller in communication withthe first and second speed motors to facilitate a smooth transitionduring a change in speed of the output shaft.
 11. The rapid infusionsystem of claim 1, further comprising a rotation sensor to monitorrevolutions of the output shaft.
 12. The rapid infusion system of claim1, further comprising a processor capable of controlling the speed ofthe first and second motors.
 13. The rapid infusion system of claim 1,wherein the differential assembly comprises a yoke, a first bevel gearin communication with the first speed motor, a second bevel gear incommunication with the second speed motor, and a pair of spider gearassemblies each having a bevel gear that transfers force from the firstor second motors to the output shaft.